MAngband used to have(and maybe still does, I'm not sure) some kind of infinite generation process, with each step becoming progressively rarer. There was a player who had dual +18s, which were obscene.

In current TomeNET, to the best of my knowledge at least, Speed rings are capped at +15, and they're super rare... my best at the moment is an 11, and I haven't found anything bigger then a +9 the entire time I've been back, within the last month or so.

That 23 must have been on the infinite process, but the odds have to be astronomical against it. The RNG must have taken pity on you in your quest to win without egos, lol.